I am completely stumped by the 12 v conversion on my case 310c that someon else did. Looking on this forum, I find several threads and articles that say in a 12 v conversion to keep the 6 v coil, attach negative coil terminal to distibuter, and a ballast resister is needed (several wiring schematics are available in the forum) My case 310 has a 12 v coil (12 v is printed on it, and printed on it is a message that says a resister is needed)', and the positive coil terminal is connected to the distributer. The Alternator is a 1 wire alternator. the battery is negative grounded. I wish I felt positive on how it should be set up. I found instructions on steiner tractor for conversion kits they have, they show 6 v coil with negative terminal connected to distributer. Any help would be greatly appreciated.